Locomotive Bogie U shape bracket modelling
You could do it with some bevels:

Create the profile (use a Mirror modifier as it is symmetetrical):



Begin to bevel the vertices (ShiftCtrlB to bevel vertices, or CtrlB and click the Vertices option in the Operator box):



Do the same with all the vertices (keep the same amount of segments):



Fill the faces (it's fast if you fill the first face then only keep one edge selected and press F several times):



Extrude, bevel the edges, etc...